Band-shaped lubricating material for dry wiredrawing and process for producing same

ABSTRACT

Provided is an innovative belt-shaped lubricating material for dry wiredrawing which not only can be used under severe wiredrawing processing conditions such as those of high temperature/high pressure/high speed as well as conventional powdered or granular lubricants for dry wiredrawing but also can cope with diameter reduction to a wide range of wire diameters ranging from a small diameter to a large diameter and a wide range of linear speeds ranging from a low speed to a high speed, has excellent functionalities such as lubricity, followability, spreadability, adhesiveness, heat resistance, processability, workability, safety, durability and productivity irrespective of a processed shape, is effective in improving work environments and is friendly to the global environment. 
     The belt-shaped lubricating material for dry wiredrawing includes a film containing 10 to 90% by weight of a metal salt of a saturated fatty acid and 10 to 90% by weight of a thermoplastic resin.

TECHNICAL FIELD

The present inventions relates to a belt-shaped lubricating material for dry wiredrawing, which is used for maintaining a stable processing state by preventing seizure due to direct contact between a base material such as a wire material or a rod and a die when the base material is pulled out and reduced in diameter to perform wiredrawing.

BACKGROUND ART

Powdered or granular lubricants for dry wiredrawing are commonly used for wiredrawing processing in which a base material such as a large-diameter wire material or rod made of a metal such as iron and steel or a nonferrous metal is pulled out from a hole of a mold steel such as a die, reduced in diameter into a small-diameter wire material or rod, and plastically deformed. Such a lubricant for dry wiredrawing is used in order to prevent a base material and a die from seizing by coming into direct contact with each other, so that sliding is facilitated to maintain a stable processing state.

For example, Patent Document 1 discloses a boric acid salt-free lubricant for dry wiredrawing which contains a metal salt of a saturated fatty acid, and a boron-free water-soluble inorganic condensation compound and/or a condensation precursor compound. Such a lubricant for dry wiredrawing which includes the metal salt of the saturated fatty acid, the inorganic substance and an additive is powdered or granular. The powdered or granular lubricant for dry wiredrawing is widely used because it can be used under severe wiredrawing processing conditions such as those of high temperature/high pressure/high speed, and can cope with diameter reduction to wire diameters ranging from a small diameter to a large diameter, and linear speeds ranging from a low speed to a high speed.

As shown in FIG. 4, the powdered or granular lubricant for dry wiredrawing is put in a die box 3 in a large amount at the time of wiredrawing processing, an a part thereof is drawn into a die 4 together with a wire material 2 to form a lubricating film 6 on the wire material 2, so that direct contact between the wire material 2 and the die 4 is prevented. About 20 percent of the lubricant for dry wiredrawing 10, which is put in the die box 3, is drawn into the die 4 together with the wire material 2 and consumed, but the remainder can no longer be used for the sake of securing quality of wiredrawing because the lubricant for dry wiredrawing 10 is partially decomposed into char due to processing heat to degrade a lubricating capability, or abrasion powders of the wire material 2 or the die 4 is contaminated. Therefore, the total amount of the remainder is unwillingly discarded.

Since the recent social situation has been shifting to a society taking care of the global environment through reuse of resources, etc., the above-mentioned mass consumption/mass disposal is becoming a problem. Since the above-mentioned lubricant is powdered or granular, there is the problem of causing deterioration of work environments, health hazards to operators and environmental pollution which result from dust and the like at the time of use. Further, it is necessary to use properly or adjust the particle shape of the lubricant for dry wiredrawing according to a processed shape, leading to poor efficiency on the operator side and the producer side. In view of these problems, an innovative lubricating material for dry wiredrawing is desired which is effective in improving work environments and is friendly to the global environment, and is not powdered while allowing processability and productivity to be maintained.

PRIOR ART DOCUMENTS Patent Document

Patent Document 1: JP 2010-111767 A

SUMMARY OF INVENTION Problem to be Solved by the Invention

The present invention has been devised for solving the aforementioned problems. And an object thereof is to provide an innovative belt-shaped lubricating material for dry wiredrawing, which not only can be used under severe wiredrawing processing conditions such as those of high temperature/high pressure/high speed as well as conventional powdered or granular lubricants for dry wiredrawing but also can cope with diameter reduction to a wide range of wire diameters ranging from a small diameter to a large diameter and a wide range of linear speeds ranging from a low speed to a high speed, has excellent functionalities such as lubricity, followability, spreadability, adhesiveness, heat resistance, processability, workability, safety, durability and productivity irrespective of a processed shape, is effective in improving work environments and is friendly to the global environment. And other objects thereof are to provide a method for production thereof, and a wiredrawing method using the same.

Means for Solving Problem

The present invention is made for achieving the aforementioned object. A belt-shaped lubricating material for dry wiredrawing of the present invention comprises: a film containing 10 to 90% by weight of a metal salt of a saturated fatty acid and 10 to 90% by weight of a thermoplastic resin,

In the belt-shaped lubricating material for dry wiredrawing, the saturated fatty acid may be butyric acid, caproic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, montanoic acid and/or melissic acid.

In the belt-shaped lubricating material for dry wiredrawing, the thermoplastic resin may be polyethylene, polypropylene, polystyrene, an acrylonitrile/styrene copolymer resin, an acrylonitrile/butadiene/styrene copolymer resin, an ethylene/vinyl acetate copolymer resin, a methacryl resin, polyvinyl chloride, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polymethylpentene, polycarbonate, polyphenylene sulfide, polyetheretherketone, polytetrafluoroethylene, polyetherimide, polyarylate, polysulphone, polyethersulfone and/or polyamideimide

In the belt-shaped lubricating material for dry wiredrawing, the metal salt may be a lithium salt, a sodium salt, a potassium salt, a calcium salt, a magnesium salt, an aluminum salt, a zinc salt, a barium salt and/or a composite metal salt thereof.

The belt-shaped lubricating material for dry wiredrawing may further include boric acid, a boric acid salt, a phosphoric acid salt, a sulfuric acid salt, a carbonic acid salt, a nitric acid salt, slaked lime, titanium oxide, talc, mica, graphite, molybdenum disulfide, a layered double hydroxide and/or sulfur.

A method for production of a belt-shaped lubricating material for dry wiredrawing comprises: heating and kneading 10 to 90% by weight of a metal salt of a saturated fatty acid and 10 to 90% by weight of a thermoplastic resin to prepare a mixture; forming the mixture into a film; and forming the film into a belt shape.

A wiredrawing method comprises: covering a base material to be subjected to a wiredrawing treatment with the belt-shaped lubricating material for dry wiredrawing according to claim 1; and passing the base material through a hole of a die and continuously pulling out the base material therefrom to be reduced in diameter, in order to perform wiredrawing.

In the wiredrawing method, the base material may be wound with or held by the belt-shaped lubricating material for dry wiredrawing to cover the base material.

In the wiredrawing method, the belt-shaped lubricating material for dry wiredrawing may be guided by a roller and wound around the base material to cover the base material.

In the wiredrawing method, the base material may be made of a metal.

Advantageous Effects of the Invention

A belt-shaped lubricating material for dry wiredrawing according to the present invention is drawn into a die together with a base material to be subjected to processing such as wiredrawing processing irrespective of a processed shape, and forms a lubricating film on the base material to prevent seizure due to direct contact between the base material and the die, so that a stable processing state can be maintained. For wiredrawing processing conditions, the belt-shaped lubricating material for dry wiredrawing can be used under severe conditions such as those of high temperature/high pressure/high speed, and can cope with diameter reduction to a wide range of wire diameters ranging from a small diameter to a large diameter and a wide range of linear speeds ranging from a low speed to a high speed.

When conventional powdered or granular lubricants for dry wiredrawing is used, one-time use amount thereof is large and they generate wastes in an amount as large as 80 percent without being completely consumed. Whence, the conventional powdered or granular lubricants are unproductive. Unlike conventional powdered or granular lubricants for dry wiredrawing, the present belt-shaped lubricating material for dry wiredrawing, owing to the belt shape, can be completely consumed, while the one-time use amount is kept low without causing mass consumption/mass disposal. And the present belt-shaped lubricating material for dry wiredrawing coinstantaneously exhibit excellent functional effects such as those of lubricity, followability, spreadability, adhesiveness, heat resistance, processability and durability. When several stages of reduction of the wire diameter in a wire material as a base material are required, usually a lubricant for dry wiredrawing is needed for each stage. However the present belt-shaped lubricating material for dry wiredrawing can be used only at the initial time or interruptedly to form an adequate lubricating film on the surface of the wire material and to maintain the effect thereof, so that production efficiency and cost effectiveness can be improved.

The belt-shaped lubricating material for dry wiredrawing of the present invention can be safely used without causing deterioration of work environments, health hazards to operators and environmental pollution which result from dust generated in association with the powdered or granular shape, and is friendly to the global environment.

According to a method for production of a belt-shaped lubricating material for dry wiredrawing in the present invention, a belt-shaped lubricating material for dry wiredrawing which is formed into film-shape and is capable of exhibiting excellent effects such as those of lubricity, followability, spreadability, adhesiveness, heat resistance, processability and durability can be conveniently and efficiently produced.

According to a wiredrawing method of the present invention, a processed base material to be reduced in diameter to perform wiredrawing can be reliably plastically deformed using a belt-shaped lubricating material for dry wiredrawing, and can be reduced in diameter repeatedly without necessity to wind the belt-shaped lubricating material for dry wiredrawing again, thus being efficiency.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing an outline of a use state of a belt-shaped lubricating material for dry wiredrawing to which the present invention is applied.

FIG. 2 is a perspective view showing a midway stage of winding a belt-shaped lubricating material for dry wiredrawing around a wire material using a wiredrawing method to which the present invention is applied.

FIG. 3 is a perspective view showing a midway stage of holding a base material by a belt-shaped lubricating material for dry wiredrawing while winding the lubricating material around the wire material using a wiredrawing method to which the present invention is applied.

FIG. 4 is a perspective view showing an outline of a use state of a lubricant for dry wiredrawing to which the present invention is not applied.

EXPLANATIONS OF LETTERS OR NUMERALS

-   1: a belt-shaped lubricating material for dry wiredrawing, 2: a wire     material, 3: a die box, 4: a die, reference numeral, 5: a die hole,     6: a lubricating film, 7 a, 7 b and 7 c: a pair of rollers, 10: a     lubricant for dry wiredrawing.

MODE FOR CARRYING OUT THE INVENTION

Embodiments for carrying out the present invention will be described in detail below, but the scope of the present invention is not limited to these embodiments.

A belt-shaped lubricating material for dry wiredrawing according to the present invention includes a film containing 10 to 90% by weight of a metal salt of a saturated fatty acid and 10 to 90% by weight of a thermoplastic resin in a uniformly kneaded state, and is formed in a belt shape.

The saturated fatty acid that constitutes the metal salt of a saturated fatty acid is a straight-chain, branched-chain or cyclic saturated fatty acid having 3 to 29 carbon atoms. Specific examples include butyric acid, caproic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, montanoic acid and melissic acid. Among them, myristic acid, palmitic acid and stearic acid, which are industrially available, are preferable.

Examples of the metal salt that constitutes the metal salt of the saturated fatty acid include a lithium salt, a sodium salt, a potassium salt, a calcium salt, a magnesium salt, an aluminum salt, a zinc salt, a barium salt and/or a composite metal salt. Among them, a lithium salt, a sodium salt, a potassium salt, a calcium salt, a magnesium salt, an aluminum salt and a barium salt are preferable. The sodium salt is water-soluble, and can be suitably used in conditions for processing of a base material for plating, which require a step of washing a base material in a surface treatment thereof. On the other hand, a calcium salt is water-insoluble, and can be suitably used in conditions for processing of a base material, which do not require a plating treatment or a water washing step. The lithium salt and the potassium salt are preferable for improving the heat resistance of the belt-shaped lubricating material for dry wiredrawing. And the magnesium salt and the aluminum salt are preferable for improving adhesiveness to a wire material so that the uniform film is easily formed on the surface of the wire material when the wire material is drawn into a die. Further, the barium salt can improve heat resistance for the calcium salt when used with the calcium salt.

These metal salts of the saturated fatty acid may be used alone or may be used in combination of two or more thereof. The metal salt of the saturated fatty acid is contained in the belt-shaped lubricating material for dry wiredrawing in an amount of 10 to 90% by weight, preferably 50% by weight, more preferably 30% by weight. If the content of the metal salt of the saturated fatty acid is less than 10% by weight or more than 90% by weight, effects such as those of heat resistance and lubricity may be reduced.

Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, an acrylonitrile/styrene copolymer resin, an acrylonitrile/butadiene/styrene copolymer resin, an ethylene/vinyl acetate copolymer resin, a methacryl resin, polyvinyl chloride, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polymethylpentene, polycarbonate, polyphenylene sulfide, polyetheretherketone, polytetrafluoroethylene, polyetherimide, polyarylate, polysulphone, polyethersulfone and/or polyamideimide. These thermoplastic resins may be used alone or may be used in combination of two or more thereof. Among them, polyethersulphone which is excellent in heat stability is preferable because a belt-shaped lubricating material for dry wiredrawing, which is excellent in heat resistance, can be provided thereby.

The thermoplastic resin is contained in the belt-shaped lubricating material for dry wiredrawing in an amount of 10 to 90% by weight, preferably 30% by weight, more preferably 50% by weight. If the content of the thermoplastic resin is less than 10% by weight or more than 90% by weight, effects may be reduced such as heat resistance and lubricity are deteriorated and formation in a belt shape becomes difficult.

The belt-shaped lubricating material for dry wiredrawing according to the present invention may contain an inorganic substance and/or an additive as necessary in addition to the metal salt of the saturated fatty acid and the thermoplastic resin. The content of the inorganic substance and/or the additive is within an extent of not impairing the effect of the belt-shaped lubricating material for dry wiredrawing, and is 10 to 40% by weight in the belt-shaped lubricating material for dry wiredrawing.

Examples of the inorganic substance include boric acid, a boric acid salt, a phosphoric acid salt, a sulfuric acid salt, a carbonic acid salt, a nitric acid salt, slaked lime, titanium oxide, talc, mica, graphite, molybdenum disulfide, a layered double hydroxide and sulfur. These inorganic substances may be used alone or may be used in combination of two or more thereof.

These inorganic substances can improve the functionality of the belt-shaped lubricating material for dry wiredrawing when combined with the metal salt of the saturated fatty acid and the thermoplastic resin which are contained as essential components. As a preferred combination of the metal salt of the saturated fatty acid and the inorganic substance, for example, preferably boric acid that is the water-soluble inorganic substance is contained when the metal salt of the saturated fatty acid is the sodium salt of the saturated fatty acid. Also preferably slaked lime that is the water-insoluble inorganic substance is contained when the metal salt of the saturated fatty acid is the potassium salt of the saturated fatty acid.

Examples of the additive include boric acid, a boric acid salt, a phosphoric acid salt, a sulfuric acid salt, a carbonic acid salt, a nitric acid salt, slaked lime, titanium oxide, talc, mica, graphite, molybdenum disulfide, a layered double hydroxide and sulfur. These additives may be used alone or may be used in combination of two or more thereof.

The belt-shaped lubricating material for dry wiredrawing according to the present invention is produced in the following manner.

10 to 90 parts by weight of a metal salt of a saturated fatty acid which is obtained by reacting a heated/melted saturated fatty acid with a compound having a metal that constitutes the metal salt of the saturated fatty acid, and 10 to 90 parts by weight of a thermoplastic resin are mixed and heated/melted using a heating kneader. A solid obtained after uniformly kneading the mixture is pressed with a roll press or a heating-type press machine to be formed into a sheet shape, a film shape or a membrane shape, and passed through a sheet cutter to be finished in a belt shape, thereby obtaining a belt-shaped lubricating material for dry wiredrawing.

An inorganic substance or an additive may be mixed in the metal salt of the saturated fatty acid beforehand as necessary. The metal salt of the saturated fatty acid can be used in the form of powders, granules, lump grains or solids.

The width, thickness and length of the obtained belt-shaped lubricating material for dry wiredrawing are not particularly limited, and are appropriately set according to a base material and wiredrawing processing conditions. A sheet of about several dozen cm to 1 m may be wound in a sheet roll shape, and used as such as a belt-shaped lubricating material, or may be appropriately cut and wound into a tape roll shape, and used as a belt-shaped lubricating material.

The width of the belt-shaped lubricating material for dry wiredrawing is appropriately adjusted according to a shape, diameter, length and materials of the base material in wiredrawing processing, and is not particularly limited, but is preferably a width which enables a lubricating film to be formed on the surface of the base material. And the width thereof is approximately comparable to the diameter of the base material.

The thickness of the belt-shaped lubricating material for dry wiredrawing is appropriately adjusted according to a shape, diameter, length and materials of the base material in wiredrawing processing, and is not particularly limited, but the optimum thickness varies depending on a die semi-angle. When the film thickness of the belt-shaped lubricating material for dry wiredrawing is excessively thick, it may not be drawn into a die together with the base material.

The obtained belt-shaped lubricating material for dry wiredrawing is drawn into a die 4 together with a wire material 2 as a processed base material made of a metal and used at the time of wiredrawing processing using, for example, the die 4 within a die box 3 as shown in FIG. 1. The method of wiredrawing processing is, for example, as follows. The belt-shaped lubricating material for dry wiredrawing 1 is placed in conformity to a die hole 5 together with the wire material 2, and drawn into the die 4 while being wound around the wire material 2 while the wire material 2 is drawn into the die 4. When the wire material 2 is pulled out from the die 4, it becomes the desired wire material 2 subjected to plastic deformation and wiredrawing processing. And the belt-shaped lubricating material for dry wiredrawing 1, which is drawn into the die 4 together with the wire material 2, forms a lubricating film 6 on the surface of the wire material 2 through pressure contact and heat contact.

The belt-shaped lubricating material for dry wiredrawing 1 may be helically wound around the wire material 2 beforehand and used, or may be used with the wire material 2 held vertically or laterally by the lubricating material. Therefore, the shape of the belt-shaped lubricating material for dry wiredrawing 1 is not limited to a flat shape or a smooth shape as long as it is a belt-shaped film, and may have a waviness, a kink, a torsion or a warpage.

A roller for winding may be used when the belt-shaped lubricating material for dry wiredrawing 1 is wound around the wire material 2. For example, as shown in FIG. 2, the wire material 2 and the belt-shaped lubricating material for dry wiredrawing 1 may be held by a pair of left and right rollers 7 a with the latter made along the former, and the belt-shaped lubricating material for dry wiredrawing 1 may be twisted, and the wire material 2 and the belt-shaped lubricating material for dry wiredrawing 1 may be held by a pair of upper and lower rollers 7 b so as to wind the latter around the former, and rotated. In this case, the wire material 2 can be wound with the belt-shaped lubricating material for dry wiredrawing 1 in an enclosing manner and thereby covered, and may be drawn into the die hole 5 of the die 4 while being kept in this state. Each of a pair of left and right rollers 7 a and a pair of upper and lower rollers 7 b may rotate automatically as the base material is pulled out from the die hole 5, or may rotate itself by motive power of a driving source (not shown).

When the somewhat wide belt-shaped lubricating material for dry wiredrawing 1 is wound around the wire material 2, the wire material 2 and the belt-shaped lubricating material for dry wiredrawing 1, with which the wire material is covered in an enclosing manner along the shape thereof, may be held by a pair of left and right rollers 7 c recessed at the middle part of the body, and the wire material 2 may be thereby enclosed by and wound with the belt-shaped lubricating material for dry wiredrawing 1, and drawn into the die hole 5 of the die 4 while being kept in this state as shown in FIG. 3.

Wiredrawing processing conditions are not particularly limited, and those similar to conditions for conventional lubricants for dry wiredrawing can be employed.

The base material is not particularly limited as long as it is made of a metal such as iron and steel, and specific examples include a wire material, a wire, a pipe, a bar and a rod.

The base material may be pretreated as necessary. Specific examples of the pretreatment include surface treatments such as an acid treatment, bending, shot blasting and air blasting.

Description of Embodiments

Embodiments of the present invention will be described in detail below, but the scope of the present invention is not limited to the Embodiments.

An example of experimentally producing a belt-shaped lubricating material for dry wiredrawing, to which the present invention is applied, is shown in Example 1, a powdered lubricant for dry wiredrawing, to which the present invention is not applied, is shown in Comparative Example 1, and belt-shaped polyethylene, to which the present invention is not applied, is shown in Comparative Example 2.

EXAMPLE 1

In a reaction vessel equipped with a stirrer, 75 parts by weight of industrial stearic acid were heated/melted while being stirred, and 25 parts by weight of slaked lime were then added. Heating/stirring was continued until the mixture became viscous. When the mixture was hardened, heating/stirring was stopped, and the mixture was taken out and cooled, and ground so that the passage rate in a 500 mesh sieve was about 60%, thereby obtaining a calcium-based lubricant as a metal salt of a saturated fatty acid. 70 parts by weight the obtained metal salt of the saturated fatty acid and 20 parts by weight of polyethylene as a thermoplastic resin were heated/kneaded at 180° C. using a heating kneader (trade name: Labo Plasto Mill). The obtained solid was formed into a sheet so as to have a film thickness of 0.5 mm or less using a heating-type press machine, and then cut into a belt having a width of 8 mm using a sheet cutter, thereby obtaining a belt-shaped lubricating material for dry wiredrawing.

COMPARATIVE EXAMPLE 1

In a reaction vessel equipped with a stirrer, 75 parts by weight of industrial stearic acid were heated/melted while being stirred, and 25 parts by weight of slaked lime were then added. Heating/stirring was continued until the mixture became viscous. When the mixture was hardened, heating/stirring was stopped, and the mixture was taken out and cooled, and ground so that the passage rate in a 500 mesh sieve was about 60%, thereby obtaining a calcium-based lubricant for dry wiredrawing.

COMPARATIVE EXAMPLE 2

Polyethylene was heated/kneaded at 180° C. using a heating kneader (trade name: Labo Plasto Mill). The obtained solid was formed into a sheet so as to have a film thickness of 0.5 mm or less using a heating-type press machine, and then cut into a belt to obtain belt-shaped polyethylene.

(Performance Evaluation of Wiredrawing Processing)

A performance evaluation was made for wiredrawing processing performed by a wiredrawing machine using, as a lubricant for a wire material, each of the belt-shaped lubricating material for dry wiredrawing in Example 1, the calcium-based lubricant for dry wiredrawing in Comparative Example 1 and the belt-shaped polyethylene in Comparative Example 2.

A wire material (carbon steel 72A material) as a base material was freed of oxidized scales on the surface of the processed wire material through washing by an acid using a 12 wt % aqueous hydrochloric acid solution, then washed with water several times, and immersed in a 1 wt % aqueous borax solution heated to about 80° C. for neutralization of the acid treatment and corrosion prevention. The processed wire material was taken from the aqueous borax solution, and dried to form a borax film on the processed wire material, and pretreatment processing was completed. Subsequently, 1 g of the belt-shaped lubricating material for dry wiredrawing, which was obtained in Example 1, was put in a die box, and wiredrawing of a pretreated processed wire material was performed under conditions of linear speed: 40 m/minute, reduction of wire diameter: three stages of 2.8 mmφ to 2.5 mmφ to 2.25 mmφ to 2.00 mmφ and wiredrawing force: 2 kg. In three stages of wiredrawing processing, the lubricating material was used only in the first pass, and the lubricating material was not used in the second and third passes.

Similarly, wiredrawing of processed wire materials was performed using 300 g of the calcium-based lubricant for dry wiredrawing in Comparative Example 1 and 1 g of the belt-shaped polyethylene in Comparative Example 2, respectively, in place of the lubricating material.

The results of visually observing the surfaces of the wire materials subjected to wiredrawing processing using the lubricants are shown in Table 1.

TABLE 1 Visual Observation after Wiredrawing after Wiredrawing after Wiredrawing Lubricating in First Pass in Second Pass in Third Pass Material or (2.8 mmφ (2.5 mmφ to (2.25 mmφ to Lubricant to 2.5 mmφ) 2.25 mmφ) 2.0 mmφ) Example 1 Spread in Spread in Spread in Uniform Uniform Uniform Film Shape Film Shape Film Shape Comparative Spread in Spread in Metallic Example 1 Uniform Film Shape Luster Film Shape in part Comparative Metallic — — Example 2 Luster

As is evident from Table 1, for all the wire diameters, the belt-shaped lubricating material for dry wiredrawing was spread in a uniform film shape on the surface of the wire material after wiredrawing for the belt-shaped lubricating material for dry wiredrawing in Example 1, whereas a metallic luster occurred in part due to film breakage of a lubricant for dry wiredrawing in the second and subsequent passes for the conventional powdered calcium-based lubricant for dry wiredrawing in Comparative Example 1. For the belt-shaped polyethylene, a thermoplastic resin alone, in Comparative Example 2, a lubricating film was not uniformly formed on the wire material and a metallic luster occurred from in the first pass, therefore the second pass was compelled to cancel.

The wire materials subjected to wiredrawing processing were washed with a washing agent for a wiredrawing wire material (Light-Clean A-1 manufactured by KYOEISHA CHEMICAL Co., LTD) respectively. A deposit amount of each lubricant was calculated from a difference in weight before and after washing. And then the surface of the washed wire material was observed with a laser microscope at a magnification of 400. The results thereof are shown in Table 2.

TABLE 2 Microscope Observation after Wiredrawing after Wiredrawing after Wiredrawing Lubricating in First Pass in Second Pass in Third Pass Material or (2.8 mmφ to (2.5 mmφ to (2.25 mmφ to Lubricant 2.5 mmφ) 2.25 mmφ) 2.0 mmφ) Example 1 Deposit Amount 4.2 3.7 2.6 (g/m²) Flatness Rate 10 10 30   (%) or less or less Comparative Deposit Amount 3.0 2.6 1.2 Example 1 (g/m²) Flatness Rate 10 40   70 (%) or less or over Comparative Deposit Amount 1.3 — — Example 2 (g/m²) Flatness Rate 70 — — (%) or over

As is evident from Table 2, it is found that when the belt-shaped lubricating material for dry wiredrawing in Example 1 is used, a deposit amount of the belt-shaped lubricating material for dry wiredrawing tends to be heavy, and the area ratio of flat portions generated by direct contact between the die and the wire material (flatness rate) tends to be low as compared to Comparative Examples for all the wire diameters. That is, Example 1 was confirmed to have a good wiredrawing state. On the other hand, in Comparative Example 1, the flatness rate tended to be higher than that in Example 1 in the second and subsequent passes, and seizure was observed in part after wiredrawing in the third pass. That is, Comparative Example 1 was confirmed to have a poor wiredrawing state in the third and subsequent passes. In Comparative 2, seizure was observed at many spots from the first pass. That is, Comparative Example 2 was confirmed to have a poor wiredrawing state.

The belt-shaped lubricating material for dry wiredrawing in Example 1 has improved lubricating film properties and spreadability due to interaction of a conventional lubricant for dry wiredrawing with a thermoplastic resin, and is efficiently drawn into a die because of the belt shape, so that a uniform lubricating film can be formed. Owing to the effect, efficient wiredrawing at a small amount and with good efficiency as compared to conventional lubricants for dry wiredrawing can be expected. And it is expected that because of the belt shape, deterioration of work environments, etc, resulting from dust is hard to occur as compared to conventional powdered or granular lubricants for dry wiredrawing.

INDUSTRIAL APPLICABILITY

A belt-shaped lubricating material for dry wiredrawing according to the present invention is used for wiredrawing processing in which a base material, such as a wire material, a wire, a pipe, a bar or a rod, which is made of a metal such as iron and steel and has a large diameter, is pulled out from a steel mold such as a die, and reduced in diameter, and thereafter the wire material, the rod or the like is plastically deformed to be reduced in diameter. 

1. A belt-shaped lubricating material for dry wiredrawing comprising: a film containing 10 to 90% by weight of a metal salt of a saturated fatty acid and 10 to 90% by weight of a thermoplastic resin.
 2. The belt-shaped lubricating material for dry wiredrawing according to claim 1, wherein the saturated fatty acid is butyric acid, caproic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, montanoic acid and/or melissic acid.
 3. The belt-shaped lubricating material for dry wiredrawing according to claim 1, wherein the thermoplastic resin is polyethylene, polypropylene, polystyrene, an acrylonitrile/styrene copolymer resin, an acrylonitrile/butadiene/styrene copolymer resin, an ethylene/vinyl acetate copolymer resin, a methacryl resin, polyvinyl chloride, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polymethylpentene, polycarbonate, polyphenylene sulfide, polyetheretherketone, polytetrafluoroethylene, polyetherimide, polyarylate, polysulphone, polyethersulfone and/or polyamideimide.
 4. The belt-shaped lubricating material for dry wiredrawing according to claim 1, wherein the metal salt is a lithium salt, a sodium salt, a potassium salt, a calcium salt, a magnesium salt, an aluminum salt, a zinc salt, a barium salt and/or a composite metal salt thereof.
 5. The belt-shaped lubricating material for dry wiredrawing according to claim 1, comprising boric acid, a boric acid salt, a phosphoric acid salt, a sulfuric acid salt, a carbonic acid salt, a nitric acid salt, slaked lime, titanium oxide, talc, mica, graphite, molybdenum disulfide, a layered double hydroxide and/or sulfur.
 6. A method for production of a belt-shaped lubricating material for dry wiredrawing comprising: heating and kneading 10 to 90% by weight of a metal salt of a saturated fatty acid and 10 to 90% by weight of a thermoplastic resin to prepare a mixture, forming the mixture into a film, and forming the film into a belt shape.
 7. A wiredrawing method comprising: covering a base material to be subjected to a wiredrawing treatment with the belt-shaped lubricating material for dry wiredrawing according to claim 1, and passing the base material through a hole of a die and continuously pulling out the base material therefrom to be reduced in diameter, in order to perform wiredrawing.
 8. The wiredrawing method according to claim 7, wherein the base material is wound with or held by the belt-shaped lubricating material for dry wiredrawing to cover the base material.
 9. The wiredrawing method according to claim 7, wherein the belt-shaped lubricating material for dry wiredrawing is guided by a roller and wound around the base material to cover the base material.
 10. The wiredrawing method according to claim 7, wherein the base material is made of a metal. 